The present invention relates to medical devices, in particular to expandable atherectomy burrs for creating variably sized lumens in a vessel.
Atherectomy is becoming a commonly accepted medical technique to remove deposits from a patient""s vessel. In a typical atherectomy procedure, a guide catheter and guidewire are advanced through the patient""s vasculature to the point of the occlusion. Next, a driveshaft having a burr at or near its distal end is advanced over the guidewire and the driveshaft is rotated at high speed to cause the burr to ablate deposits in the vessel. The diameter of the burr is less than the diameter of the guide catheter through which it is routed. Therefore, the size of the lumen that can be created in the vessel is also limited. If the physician wishes to create a larger lumen, another atherectomy burr with a larger diameter and perhaps a new guide catheter must be routed over the guidewire and the procedure is repeated. However, it is also well known that the risk of patient complications may increase as larger guide catheters are used. In addition, the use of multiple atherectomy burrs increases the cost and the time required to complete an atherectomy procedure. Therefore, there is a need for an atherectomy device that can create lumens in a vessel that are larger than the diameter of the guide catheter used to deliver the burr to the site of the occlusion.
The present invention is an atherectomy burr for creating variably sized lumens in a patient""s vessel. The atherectomy burr includes a distal end, a proximal end and one or more cutting members that expand radially outward as the burr rotates. Each of the cutting members has a cutting surface that ablates occluding matter from the vessel as the burr is rotated. The invention also includes a variety of mechanisms to limit expansion of the cutting members.